package com.btsk.dao.hibernate;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import org.springframework.orm.ObjectRetrievalFailureException;
import org.springframework.orm.hibernate3.HibernateTemplate;
import org.springframework.orm.hibernate3.SessionFactoryUtils;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Required;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.criterion.DetachedCriteria;
import org.hibernate.criterion.Projections;

import com.btsk.dao.GenericDao;

import java.io.Serializable;
import java.util.ArrayList;
import java.util.Collection;
import java.util.LinkedHashSet;
import java.util.List;
import java.util.Map;

/**
 * This class serves as the Base class for all other DAOs - namely to hold common CRUD methods that they might all use. You should only need to extend this
 * class when your require custom CRUD logic.
 * <p/>
 * <p>
 * To register this class in your Spring context file, use the following XML.
 * 
 * <pre>
 *      &lt;bean id="fooDao" class="com.yuweitek.mmp.dao.hibernate.GenericDaoHibernate"&gt;
 *          &lt;constructor-arg value="com.yuweitek.mmp.model.Foo"/&gt;
 *          &lt;property name="sessionFactory" ref="sessionFactory"/&gt;
 *      &lt;/bean&gt;
 * </pre>
 * 
 * @author <a href="mailto:bwnoll@gmail.com">Bryan Noll</a>
 * @param <T>
 *            a type variable
 * @param <PK>
 *            the primary key for that type
 */
public class GenericDaoHibernate<T, PK extends Serializable> implements GenericDao<T, PK>
{

    /**
     * Log variable for all child classes. Uses LogFactory.getLog(getClass()) from Commons Logging
     */
    protected final Log log = LogFactory.getLog(getClass());

    private Class<T> persistentClass;

    private HibernateTemplate hibernateTemplate;

    private SessionFactory sessionFactory;

    /**
     * Constructor that takes in a class to see which type of entity to persist. Use this constructor when subclassing.
     * 
     * @param persistentClass
     *            the class type you'd like to persist
     */
    public GenericDaoHibernate(final Class<T> persistentClass)
    {
        this.persistentClass = persistentClass;
    }

    /**
     * Constructor that takes in a class and sessionFactory for easy creation of DAO.
     * 
     * @param persistentClass
     *            the class type you'd like to persist
     * @param sessionFactory
     *            the pre-configured Hibernate SessionFactory
     */
    public GenericDaoHibernate(final Class<T> persistentClass, SessionFactory sessionFactory)
    {
        this.persistentClass = persistentClass;
        this.sessionFactory = sessionFactory;
        this.hibernateTemplate = new HibernateTemplate(sessionFactory);
    }

    public HibernateTemplate getHibernateTemplate()
    {
        return this.hibernateTemplate;
    }

    public SessionFactory getSessionFactory()
    {
        return this.sessionFactory;
    }

    @Autowired
    @Required
    public void setSessionFactory(SessionFactory sessionFactory)
    {
        this.sessionFactory = sessionFactory;
        this.hibernateTemplate = new HibernateTemplate(sessionFactory);
    }

    /**
     * {@inheritDoc}
     */
    @SuppressWarnings("unchecked")
    public List<T> getAll()
    {
        return hibernateTemplate.loadAll(this.persistentClass);
    }

    /**
     * {@inheritDoc}
     */
    @SuppressWarnings("unchecked")
    public List<T> getAllDistinct()
    {
        Collection result = new LinkedHashSet(getAll());
        return new ArrayList(result);
    }

    /**
     * {@inheritDoc}
     */
    @SuppressWarnings("unchecked")
    public T get(PK id)
    {
        T entity = (T) hibernateTemplate.get(this.persistentClass, id);

        if (entity == null)
        {
            log.warn("Uh oh, '" + this.persistentClass + "' object with id '" + id + "' not found...");
            //throw new ObjectRetrievalFailureException(this.persistentClass, id);
        }

        return entity;
    }

    /**
     * {@inheritDoc}
     */
    @SuppressWarnings("unchecked")
    public boolean exists(PK id)
    {
        T entity = (T) hibernateTemplate.get(this.persistentClass, id);
        return entity != null;
    }

    /**
     * {@inheritDoc}
     */
    @SuppressWarnings("unchecked")
    public T save(T object)
    {
        return (T) hibernateTemplate.merge(object);
    }

    /**
     * {@inheritDoc}
     */
    public void remove(PK id)
    {
        hibernateTemplate.delete(this.get(id));
    }

    /**
     * {@inheritDoc}
     */
    @SuppressWarnings("unchecked")
    public List<T> findByNamedQuery(String queryName, Map<String, Object> queryParams)
    {
        String[] params = new String[queryParams.size()];
        Object[] values = new Object[queryParams.size()];

        int index = 0;
        for (String s : queryParams.keySet())
        {
            params[index] = s;
            values[index++] = queryParams.get(s);
        }

        return hibernateTemplate.findByNamedQueryAndNamedParam(queryName, params, values);
    }

    private boolean cacheQueries = true;

    @SuppressWarnings("unchecked")
    public List<T> findByCriteria(final DetachedCriteria criteria)
    {
        if (cacheQueries)
        {
            getHibernateTemplate().setCacheQueries(true);
        }
        else
        {
            getHibernateTemplate().setCacheQueries(false);
        }
        return getHibernateTemplate().findByCriteria(criteria);
    }

    @SuppressWarnings("unchecked")
    public List<T> findByCriteria(final DetachedCriteria criteria, int firstResult, int maxResults)
    {
        return getHibernateTemplate().findByCriteria(criteria, firstResult, maxResults);
    }

    public int findCountsBycriteria(final DetachedCriteria criteria)
    {
        // criteria.createAlias(arg0, arg1)
        criteria.setProjection(Projections.rowCount());
        // System.out.println(getHibernateTemplate().findByCriteria(criteria));
        return (Integer) getHibernateTemplate().findByCriteria(criteria).get(0);
    }

    public void setCacheQueries(boolean cacheQueries)
    {
        this.cacheQueries = cacheQueries;
    }

    public Session getSession(boolean allowCreate)
    {
        return SessionFactoryUtils.getSession(sessionFactory, allowCreate);
    }
}
